Effect mechanism of diamond content on tribo-chemical processing of sapphire wafers using developed clusters of diamond and ceria chemically agglomerated abrasive cluster

Abstract

To enhance the material removal rate (MRR) and surface quality of sapphire wafers during lapping, this study proposes a new method for preparing chemically agglomerated abrasive clusters (CAAC). Using this method, five distinct CAAC abrasives, each with a different diamond content, were prepared for lapping experiments on sapphire wafers. MRR and surface roughness Ra were used as evaluation indicators to elucidate the removal behavior of CAAC abrasive particles during the lapping of sapphire wafers. The study analyzed changes in the friction curve, the elemental composition of the sapphire surface before and after lapping, and the microscopic morphology of the CAAC abrasives. The results indicate that #4 CAAC demonstrates the highest MRR and favorable surface quality among the tested variants. Specifically, #4 CAAC achieved the highest removal rate of 380.267 nm/min and the lowest surface roughness of 33.978 nm, outperforming #1, #2, #3, and #5 CAAC. Compared to W50 single crystalline diamond (W50 SCD) of equivalent grain size, the MRR increased by a factor of 3.1. Furthermore, within a certain range, the machining performance of CAAC improves with an increase in diamond content; however, both excessively high and low diamond contents negatively impact overall performance. When the diamond content in CAAC reaches 42 %, machinability is optimized. This method enhances the processing efficiency of sapphire wafers, improves surface quality, and offers innovative approaches for efficient and cost-effective sapphire wafer processing.